NoState Prefetch: nostate prefetch browser tests.

chrome/browser/prerender/prerender_contents.h

Index: chrome/browser/prerender/prerender_contents.h
diff --git a/chrome/browser/prerender/prerender_contents.h b/chrome/browser/prerender/prerender_contents.h
index 9e08bafe8a8b7f67f6302966b9045db5c892e9c0..6098e5bc5b3b5ae7549d23359871df84ff361bd6 100644
--- a/chrome/browser/prerender/prerender_contents.h
+++ b/chrome/browser/prerender/prerender_contents.h
@@ -204,7 +204,7 @@ class PrerenderContents : public content::NotificationObserver,
 
   // Sets the final status, calls OnDestroy and adds |this| to the
   // PrerenderManager's pending deletes list.
-  void Destroy(FinalStatus reason);
+  virtual void Destroy(FinalStatus reason);

[droger, 2016/09/20 10:57:19]

Add a comment:
// Virtual for testing.

I think it would be fine to have the observer in the base class instead, but I
don't have a strong preference.

[mattcary, 2016/09/21 08:45:10]

That's not a bad idea. Why multiply observers if we don't need to?

And looking closer, it seems that OnPrerenderStop already fits the bill, so I
don't need a new OnDestroy call. Yay!

I did take this opportunity to clean up the observer class which was a little
messy.

 
   // Called by the history tab helper with the information that it woudl have
   // added to the history service had this web contents not been used for